Bio Test

What is a virus?

A piece of genetic information (DNA or RNA) inside a protein shell. Can only replicate inside living cells, and can affect all organisms.

How do viruses infect cells?

attach to cells and use their genetic material to take over the cell's function. The cell then creates new virus particles, which spread to other cells.

Viruses vs Bacteria?

Bacteria are living cells (and can be killed by antibiotics). Viruses do not fully meet the definition of a living thing. Viruses are tiny- much smaller than cells.

Lytic replication cycle?

Virus tells infected cell to make new viruses, and the cell pops open and spreads viruses.

Lysogenic replication cycles?

Virus sneaks its instructions into the infected cell's DNA. Cell copies the viral DNA along with its own.

The COVID-19 virus?

an illness caused by a virus called SARS-CoV-2. It belongs to a family of viruses called coronaviruses.

What is the immune system?

A system of cells, tissues and organs that help the body fight off foreign invaders and other diseases.

What is INNATE immunity?

First line of defense against invaders, and you're born with it. Made up of physical barriers (skin, mucous membranes, etc) and cells that fight infection. NOT specific in how or what it fights off, but it's FAST.

What is ADAPTIVE immunity?

targets specific pathogens using
antibodies. After clearing the body of the pathogen, it retains a memory in case the infection should happen again. It's SLOW but SPECIFIC in what it fights.

T cells

have three jobs: activate other immune cells to start the adaptive response, kill sick or infected cells, and remember past infections.

B cells

make antibodies and also remember past infections.

What are antibodies?

are molecules the body creates to tag and eliminate foreign invaders. The things they recognize and bind to are called antigens

What is a vaccine?

a substance that is used to stimulate the body's immune response against a disease.

How do we determine vaccine effectiveness?

Large groups of people get the vaccine or a placebo shot. Then we see how many people get sick in each group.

What was the first vaccine?

The smallpox vaccine. By exposing a person to a similar virus called cowpox, people developed immunity to the much more dangerous virus that causes smallpox.

How do vaccines work?

train the immune system to recognize a pathogen, making it much easier to fight off future infections by that pathogen.

How do the COVID
mRNA vaccines work?

These vaccines contain the mRNA code to make the virus' spike protein. The body produces antibodies that bind to the spike and help destroy the virus.

What is ZOONOSIS?

The process of a virus jumping from an animal into a human being. Can happen through farming, hunting, etc.

What are viral VARIANTS?

Versions of a virus with significant changes in their genetic code. These genetic changes can alter how they affect human beings.

How do viral variants arise?

Every time the virus reproduces, there's a chance of a copying error leading to mutations. On rare occasions, those mutations can affect how the virus impacts us.

Endemic

means a disease is always present in a region or population.

Epidemic

means a disease is spreading to a large group of people.

Pandemic

means an epidemic has spread around the world.

How do pandemics end?

There's no single answer. Smallpox was eradicated by vaccination. Some keep going until they run out of people to infect, and some become endemic.